
Now Playing: Why kids should stay away from sports drinks
Now Playing: Mom and 2 daughters lose more than 150 pounds
Now Playing: This son saved his mom’s life with an organ donation
Now Playing: Teen wakes up after being declared brain dead
Now Playing: Miraculous recovery for 13-year-old declared brain dead
Now Playing: How to find a healthy relationship with your smartphone
Now Playing: What is E. Coli?
Now Playing: High school student hospitalized after prom party hypnosis
Now Playing: Meredith Vieira, Richard Cohen on battle with MS
Now Playing: What are the potential dangers of ‘Juul’-ing?
Now Playing: First death reported in romaine lettuce E. coli outbreak
Now Playing: CDC issues ticks, mosquitoes warning ahead of summer
Now Playing: Teen credits Apple Watch for saving her life
Now Playing: Researchers working on possible autism test for children
Now Playing: Apple Watch saves teenage girl’s life
Now Playing: Why allergy season gets worse every year
Now Playing: College offers a business class on spin bikes
Now Playing: ABC News’ Rob Marciano rides a mechanical bull on ‘GMA’
Now Playing: Renowned breast cancer surgeon Dr. Kristi Funk opens up about her new book
Now Playing: College students take business class on spin bikes